Determinants and Causation - Part 2

Question 1

What is a determinant?

Answer 1

Any factor or variable that can affect the frequency of disease occurence in a population

Question 2

What does understanding the determinant help us to do?

Answer 2

If we understand the determinant we can then possibly interven

Question 3

What does it mean that associations can be causal or not?

Answer 3

Two outcomes can have association because they are determined by a single determinant, however, just because they are associated, does not mean that the one causes the other

Question 4

What are confounders?

Answer 4

Uncontrolled and unmeasured differences among groups that alternatively explain the outcome

• differences that can account for what you are seeing, which you arent accounting or controlling for in your experiment and therefore it is missed

Question 5

4 methods for developing a causal hypothesis?

Answer 5

1. Method of difference
2. Method of agreement
3. Method of concomitant variation
4. Method of analogy

Question 6

What is a method of difference?

Answer 6

If a disease occurs in two situation at different frequencies, any factors that are different between the situations could be causal

Question 7

What is method of agreement?

Answer 7

If a factor is common to a number of different circumstances in which a disease is present, then the factor may be the cause of the disease

Question 8

What is method of concomitant variation?

Answer 8

If the frequency or strength of a factor varies continuously with the frequency of the disease, it may be a cause

Question 9

Method of analogy

Answer 9

Compare the pattern of disease under study with that of a disease that is already understood

• some cancers caused by a virus, treat new cancer as though caused by a virus to determine type

Question 10

What is a risk of using method of analogy?

Answer 10

Tend to depend upon a checklist already known, which the disease is not a method of analogy to other disease

Question 11

Koch’s 4 postulates

Answer 11

1. Microorganism must be found in abundance in all individuals suffering from the disease, but not healthy individuals
2. The microorganism must be isolated from a diseased individual and grown in pure culture
3. The cultured microorganism should cause disease when introduced into a healthy individual
4. The microorganism must be re-isolated from inoculated, diseased experimental host and identified as being identical to the original specific causative agent

Question 12

Problems with Koch’s postulates

Answer 12

1. Healthy carriers exist
2. Sometimes you cant culture an agent in the lab
3. Need a particular extrinsic factor for microbe to cause disease when introduced to healthy individual…. Ethics

Question 13

What is the goal of triangulation?

Answer 13

Not to conclusively “prove” cause and effect relationships, but rather to collect sufficient evidence, using all of the available tools and data to reach a verdict of causation which can then justify and direct management action